Mobile communications system (or wireless telecommunications system) such as those which are being developed in accordance with the Long Term Evolution (LTE) project by the Third Generation Project Partnership (3GPP) can provide a facility for communications devices to transmit or receive data for a variety of applications with high data rates within a radio coverage area provided by a mobile communications network. A wireless access interface provided by the mobile communications network configured in accordance with an LTE standard includes signal transmission techniques which can support these high data rates. There is therefore expected to be a variety of applications, which can be supported by an LTE system.
Although there are applications which require high data rates to support their operation, there are some applications in which high data rates are not required. Indeed there are some applications which are expected to be provided by more simple, less complicated communications devices such as those supporting machine type communications (MTC). Such devices are also expected to be low power devices and may include a relatively inexpensive low complexity, narrowband, transmitter and receiver. Such devices may also be deployed in locations in which radio communications conditions can make transmission and reception of signals more difficult.
A technique which has been proposed to improve a likelihood of communications devices to receive signals transmitted by a mobile communications network using an existing transmission format is to repeat a transmission of a signal representing a message from a mobile communications network. A receiver can combine the repeatedly received message to improve a likelihood of correctly detecting the message. Therefore a mobile communications network can be arranged to extend its radio coverage, particularly for less complicated mobile communications devices. Such a technique is known as coverage extension (or coverage enhancement).
However, the use of repeated message transmission so as to allow such coverage extension for narrowband transmitters and receivers may be problematic.